A method for authenticating a trusted platform based on the Tri-element Peer Authentication (TePA). The method includes the following steps: A) a second attesting system sends the first message to a first attesting system; B) the first attesting system sends a second message to the second attesting system after receiving the first message; C) the second attesting system sends a third message to a Trusted Third Party (TTP) after receiving the second message; D) the TTP sends a fourth message to the second attesting system after receiving the third message; E) the second attesting system sends a fifth message to the first attesting system after receiving the fourth message; and F) the first attesting system performs an access control after receiving the fifth message. The method for authenticating a trusted platform based on TePA of the present invention adopts the security architecture of TePA, and improves the safety of an evaluation agreement of the trusted platform, realizes the mutual evaluation of the trusted platform between the attesting systems, and extends the application ranges.